The invention relates generally to expansion anchors, and more particularly to self-cutting expansion anchors and systems.
Known self-cutting expansion anchors generally comprise a sleeve having expansion tabs that expand in a pre-drilled bore, for example in concrete, upon axial displacement about a conical head portion of a dowel or shaft. The expansion tabs include cutters that form an undercut in the pre-drilled bore as the sleeve rotates therein, as disclosed for example in U.S. Pat. Nos. 5,816,760, 5,911,550, and 5,921,733.
It is known to form the cutters of self-cutting expansion anchors with hardened alloy inserts embedded on corresponding portions of the expansion tabs thereof, as discussed in U.S. Pat. No. 5,921,733 and in German Patent No. DE 3,535,262.
An object of the present invention is to provide novel self-cutting expansion anchors and systems that overcome problems and improve upon the prior art.
Another object of the invention is to provide novel self-cutting expansion anchors and systems that are reliable and economical.
A further object of the invention is to provide novel self-cutting expansion anchors having expandable sections with hardened cutting portions formed unitarily therewith.
A further object of the invention is to provide novel self-cutting expansion anchors having at least one pair of cutting portions disposed on corresponding expandable sections located on substantially opposites sides of an anchoring shaft thereof.
A more particular object of the invention is to provide novel self-cutting expansion anchors comprising a sleeve member having a plurality of expandable sections disposed about a shaft having a generally conical portion, a heat hardened cutting portion protruding from at least some of the expandable sections of the sleeve member, the hardened cutting portions and the corresponding expandable sections are preferably unitary members.
Another more particular object of the invention is to provide novel self-cutting expansion anchors comprising a sleeve member having a plurality of expandable sections disposed about a shaft with a generally conical portion, and a cutting portion on exactly two of the plurality of expandable sections located on generally opposite sides of the shaft.
Yet another more particular object of the invention is to provide novel self-cutting expansion anchoring systems comprising an expansion sleeve member having a plurality of expandable sections disposed about a shaft, a hardened cutting portion protruding from at least some of the expandable sections of the expansion sleeve member on a portion thereof disposed toward a generally conical portion of the shaft, the hardened cutting portions and the corresponding expandable sections are unitary members, and a threaded driving sleeve member having a driving end disposed about the threaded shaft toward a driving end of the expansion sleeve member.
These and other objects, aspects, features and advantages of the present invention will become more fully apparent upon careful consideration of the following Detailed Description of the Invention and the accompanying Drawings, which may be disproportionate for ease of understanding, wherein like structure and steps are referenced generally by corresponding numerals and indicators.